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Re: svnsync backwards-compatibility with older servers (Was: Re: svn commit: r999421)

From: Stefan Sperling <stsp_at_elego.de>
Date: Tue, 21 Sep 2010 18:25:10 +0200

On Tue, Sep 21, 2010 at 05:07:49PM +0100, Jon Foster wrote:
> So... what do we do if a 1.7 svnsync connects to a <=1.6 mirror server?
> Some options are:
>
> 1) It works like 1.6 - i.e. it does buggy locking that works most of the
> time, then one day it corrupts the mirror repo.
>
> 2) It runs without even trying to do locking. This is likely to be more
> obvious to the sysadmin, so they might notice it in testing.
>
> 3) It errors out with an informative message. If the user has control
> of the mirror server, they can upgrade it to 1.7. Alternatively, if the
> user doesn't need locking (e.g. they have set up external locking), they
> can pass --disable-locking to svnsync.
>
>
> I really don't like option 1. I think Subversion should be reliable,
> and random corruption is not good. I'd like to get rid the old, buggy
> locking code.
>
> I'm not keen on option 2 either. Silently disabling a
> required-for-correctness feature seems like a really bad idea. And the
> locking has always been a documented feature (even if it's never
> worked).
>
> So I guess that leaves option 3. That's not fully backwards-compatible
> - you can't just drop in a 1.7 svnsync to replace a 1.6 svnsync, unless
> you update the server at the same time. But I feel that it's the least
> bad option.

I agree that option 3 is best. There's no point in hiding the problem
from the user in the name of backwards compatibility.

Daniel, this can easily be done on trunk, too, if you decide to merge
the branch back soon.

Stefan
Received on 2010-09-21 18:26:01 CEST

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